Ophthalmologic apparatus and ophthalmologic system

ABSTRACT

An ophthalmologic apparatus includes: a head unit having an optical system capable of receiving light reflected from a subject&#39;s eye; a drive mechanism that movably holds the head unit; an alignment detection unit that detects a position of the subject&#39;s eye relative to the head unit; and a control unit that controls the drive mechanism. The drive mechanism includes at least two arms rotatably connected together, at least two first rotation support mechanisms and at least three second rotation support mechanisms which allow the head unit to move, and at least five driving units for driving the rotation support mechanisms. The control unit is capable of controlling the driving units using a measurement result of the alignment measuring unit to align the head unit and the subject&#39;s eye with each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of prior-filed U.S. Utility patentapplication Ser. No. 16/937,626, filed Jul. 24, 2020, which claimspriority to Japanese Patent Application No. 2019-139397, filed Jul. 30,2019, the entire disclosure of which is incorporated by referenceherein.

BACKGROUND

The present disclosure relates to an ophthalmologic apparatus andophthalmologic system used for measurement and imaging of a subject'seye.

Ophthalmologic apparatuses include, for example, an ophthalmologicmeasurement apparatus for measuring the characteristics of a subject'seye, and an ophthalmologic imaging apparatus for capturing an image ofthe subject's eye. In order to measure, or capture an image of, thesubject's eye, the positions of the subject's eye (subject) and theophthalmologic apparatus need to be adjusted. Therefore, ophthalmologicapparatuses that can move relative to the subject's eye has beenproposed.

Japanese Unexamined Patent Publication No. 2018-51337 discloses anophthalmologic apparatus having an apparatus body provided for a baseunit via a driving unit. The apparatus body described in JapaneseUnexamined Patent Publication No. 2018-51337 is provided with anintraocular pressure measurement unit that measures an intraocularpressure of the subject's eye, and an ocular characteristic measurementunit that measures other optical characteristics (ocularcharacteristics) of the subject's eye.

The driving unit described in Japanese Unexamined Patent Publication No.2018-51337 moves the apparatus body with respect to the base unit in anup-down direction (Y-axis direction), a front-rear direction (Z-axisdirection), and a left-right direction (X-axis direction) orthogonal tothese directions. Specifically, the driving unit described in JapaneseUnexamined Patent Publication No. 2018-51337 includes a Y-axis drivingportion, a Z-axis driving portion, and an X-axis driving portion, andfunctions as a slide mechanism that slides the apparatus body in theup-down direction (Y-axis direction), the front-rear direction (Z-axisdirection), and the left-right direction (X-axis direction) with respectto the base unit.

SUMMARY

However, if the apparatus is provided with a slide mechanism that slidesthe apparatus body having an examination unit including a measurementunit and an imaging unit, the driving unit becomes large in size, whichmakes the downsizing of the ophthalmologic apparatus difficult. Further,if this mechanism is used to give the apparatus body a wider movablerange and a higher degree of freedom, the driving unit disadvantageouslybecomes much larger in size. If another mechanism for freely changingthe orientation and inclination of the examination unit is provided, thedriving unit becomes much larger in size.

The present disclosure has been made to solve the above-describedproblem, and it is therefore an object of the present disclosure toprovide an ophthalmologic apparatus and an ophthalmologic system thatare downsized, and give a measurement unit an increased degree ofpositioning freedom.

In order to achieve the above-described object, an ophthalmologicapparatus of the present disclosure is an ophthalmologic apparatus foroptically acquiring information of a subject's eye. The ophthalmologicapparatus includes: a head unit having an optical system capable ofreceiving light reflected from the subject's eye; a drive mechanism thatmovably holds the head unit; an alignment detection unit that detects aposition of the subject's eye relative to the head unit; and a controlunit that controls the drive mechanism. The drive mechanism includes atleast two arms rotatably connected together, at least two first rotationsupport mechanisms each of which is rotatable about a first axis, atleast three second rotation support mechanisms each of which isrotatable about a second axis different in direction from the firstaxis, and at least five driving units for driving the first and secondrotation support mechanisms, the first and second rotation supportmechanisms allowing the head unit to move. The control unit is capableof controlling the driving units using a detection result of thealignment detection unit to align the head unit and the subject's eyewith each other.

Further, in order to achieve the above-described object, anophthalmologic system of the present disclosure is an ophthalmologicsystem for optically acquiring information of a subject's eye. Theophthalmologic system includes: a head unit having an optical systemcapable of receiving light reflected from the subject's eye; a drivemechanism that movably holds the head unit; an alignment detection unitthat detects a position of the subject's eye relative to the head unit;a control unit that controls the drive mechanism; and a terminal devicethat receives information about the light received by the optical systemvia a network. The drive mechanism includes at least two arms rotatablyconnected together, at least two first rotation support mechanisms eachof which is rotatable about a first axis, at least three second rotationsupport mechanisms each of which is rotatable about a second axisdifferent in direction from the first axis, and at least five drivingunits for driving the first and second rotation support mechanisms, thefirst and second rotation mechanisms allowing the head unit to move. Thecontrol unit is capable of controlling the driving units using adetection result of the alignment detection unit to align the head unitand the subject's eye with each other.

The present disclosure offering the above-described solution can providean ophthalmologic apparatus and an ophthalmologic system which aredownsized, and give a measurement unit an increased degree ofpositioning freedom.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a configuration of anophthalmologic apparatus according to a first embodiment of the presentdisclosure.

FIG. 2 is a perspective view illustrating the ophthalmologic apparatusaccording to the first embodiment of the present disclosure.

FIG. 3 is a block diagram illustrating the ophthalmologic apparatusaccording to the first embodiment of the present disclosure.

FIG. 4 is a schematic view illustrating a variation of a drive mechanismof the ophthalmologic apparatus according to the first embodiment of thepresent disclosure.

FIG. 5 is a perspective view illustrating another variation of theophthalmologic apparatus according to the first embodiment of thepresent disclosure.

FIG. 6 is a perspective view partially illustrating an ophthalmologicapparatus according to a second embodiment of the present disclosure.

FIG. 7 is a block diagram illustrating the ophthalmologic apparatusaccording to the second embodiment of the present disclosure.

FIG. 8A is a schematic top view illustrating an operation of a head unitof the ophthalmologic apparatus according to the second embodiment ofthe present disclosure.

FIG. 8B is a schematic top view illustrating an operation of the headunit of the ophthalmologic apparatus according to the second embodimentof the present disclosure.

FIG. 9A is a schematic side view illustrating an operation of the headunit of the ophthalmologic apparatus according to the second embodimentof the present disclosure.

FIG. 9B is a schematic side view illustrating an operation of the headunit of the ophthalmologic apparatus according to the second embodimentof the present disclosure.

FIG. 10 is a block diagram illustrating an ophthalmologic systemaccording to a third embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail withreference to the drawings.

First Embodiment

A first embodiment of the present disclosure will be described below.

FIG. 1 is a side view illustrating an ophthalmologic apparatus of thefirst embodiment. An ophthalmologic apparatus 10 of the presentembodiment irradiates a subject's eye E with light, and acquiresinformation about the characteristics of the subject's eye based on thedetection result of light reflected from the subject's eye E.Specifically, the ophthalmologic apparatus 10 of the present embodimentis an ophthalmologic apparatus that examines the subject's eye E basedon the light reflected from the subject's eye E. The examination by theophthalmologic apparatus generally includes measurement for acquiringthe characteristics of the subject's eye E, and photographing forcapturing an image of the subject's eye E.

Examples of an ophthalmologic measurement apparatus include: an eyerefraction test apparatus (a refractometer, a keratometer) that measuresrefractive characteristics of the subject's eye; a tonometer; a specularmicroscope that acquires corneal characteristics (e.g., thickness andcellular distribution of cornea); a wavefront analyzer that acquiresaberration information of the subject's eye using a Hartmann-Shacksensor; and an eye axis length measurement apparatus. More specifically,the refractometer measures eye refraction by irradiating a posteriorsegment with a ring image, and analyzing a reflected image of theposterior segment captured by the camera. The keratometer measures theeye refraction by irradiating an anterior segment with a ring image, andanalyzing a reflected image captured by an anterior segment

Examples of an ophthalmologic imaging apparatus include: an opticalcoherence tomography that acquires a cross-sectional image using opticalcoherence tomography (OCT); a fundus camera that captures a fundusimage; a scanning laser ophthalmoscope (SLO) that captures a fundusimage through laser scanning using a confocal optical system; and a slitlamp that uses slit light and cuts an optical section of the cornea toobtain an image.

FIG. 1 is a schematic view illustrating the ophthalmologic apparatus 10of the first embodiment. FIG. 2 is a perspective view illustrating adrive mechanism 30 of the ophthalmologic apparatus 10 of the firstembodiment. FIG. 3 is a block diagram illustrating connection amongcomponents of the ophthalmologic apparatus 10 of the first embodiment.The configuration of the ophthalmologic apparatus 10 of the firstembodiment will be described below with reference to FIGS. 1, 2, and 3 .

The ophthalmologic apparatus 10 of the first embodiment includes a headunit 20, a drive mechanism 30, a display unit 74, a base unit 80, a chinsupport 81, and a forehead support 82. The head unit 20 is provided forthe base unit 80 via the drive mechanism 30.

The head unit 20 includes an intraocular pressure measurement unit (notshown), and an ocular characteristic measurement unit (not shown). Thatis, the ophthalmologic apparatus 10 of the present embodiment is ahybrid ophthalmologic apparatus including the intraocular pressuremeasurement unit and the ocular characteristic measurement unit. Theintraocular pressure measurement unit measures the intraocular pressureof the subject's eye. The ocular characteristic measurement unitmeasures other optical characteristics (ocular characteristics) of thesubject's eye. However, at least any one of a measurement unit or animaging unit provided in the head unit 20 is not limited to theintraocular pressure measurement unit and the ocular characteristicmeasurement unit. For example, the ophthalmologic apparatus 10 may be ahybrid ophthalmologic apparatus including an optical coherencetomography that acquires a cross-sectional image using OCT, and a funduscamera that captures a fundus image. Specifically, the ophthalmologicapparatus 10 of the present embodiment may be comprised of either one ofthe ophthalmologic imaging apparatus or the ophthalmic measurementapparatus described by way of examples listed above, or a plurality ofthe ophthalmologic measurement apparatuses or the ophthalmologicmeasurement apparatuses in combination. As described above, the headunit 20 includes an examination unit including at least one of animaging unit having an imaging function or a measurement unit having ameasurement function. In the present embodiment, it will be described asan example in which the head unit 20 includes, as the examination unit,the intraocular pressure measurement unit and the ocular characteristicmeasurement unit.

Each of the intraocular pressure measurement unit and the ocularcharacteristic measurement unit provided for the head unit 20 has anexamination optical system for optically examining the subject's eye E.For example, each of the intraocular pressure measurement unit and theocular characteristic measurement unit includes, as the examinationoptical system, an illumination optical system including a light source21 that irradiates the anterior segment and fundus of the subject's eyeE with illumination light, an imaging optical system including animaging camera 22 (e.g., an anterior segment camera and a fundus camera)for acquiring images of the anterior segment and fundus of the subject'seye E. The subject's eye E is irradiated with the light emitted from thelight source 21 of the examination optical system as a light beamparallel to an optical axis O1 of the examination optical system. Thehead unit 20 also includes a stereo camera 23 for alignment adjustmentso that an appropriate distance is kept between the subject's eye E andthe head unit 20. The stereo camera 23 includes at least two alignmentcameras. An alignment detection unit 72, which will be described later,can detect the position of the subject's eye E relative to the head unit20 from the information of images captured by the two alignment cameras.

The display unit 74 is comprised of a liquid crystal display, anddisplays an image such as an anterior segment image, and examinationresults of the subject's eye E under the control of the control unit 71.In the present embodiment, the display unit 74 has a touch panelfunction to serve as an operating unit 75, which can be operated by auser to perform measurement using the intraocular pressure measurementunit or the ocular characteristic measurement unit, and to move the headunit 20. If the user points at the image of the subject's eye E on thetouch panel of the display unit 74, the head unit 20 can be moved sothat the pointed position comes to the center of the panel, or can beautomatically moved through the alignment adjustment to adjust thefocus. The head unit 20 may be manually moved through the operation viathe operating unit 75. A measurement switch may be provided so that themeasurement is performed via the operation of the measurement switch.Further, a control lever or a movement operation switch may be providedso that the head unit 20 is moved via the operation of the control leveror the movement operation switch.

The chin support 81 and the forehead support 82 fix the face of thesubject with respect to the heat unit 20 during the measurement, so thatthe position of the subject's eye E is fixed with respect to theophthalmologic apparatus 10. The chin support 81 is a portion on whichthe subject places his/her chin, and the forehead support 82 is aportion with which the forehead of the subject makes contact. The headunit 20 can be moved by the drive mechanism 30 with respect to the baseunit 80. Thus, the head unit 20 is configured to be movable with respectto the subject's face fixed by the chin support 81 and the foreheadsupport 82, i.e., the subject's eye E.

In the present specification, the gravity direction is defined as a Ydirection which is a vertical direction, and directions perpendicular tothe gravity direction and orthogonal to each other are defined as an Xdirection and a Z direction. Further, a direction along a plane definedby the X and Z directions is defined as a horizontal direction. Aleft-right direction in FIG. 1 will be regarded as the Z direction (thedirection of the optical axis O1 of the examination optical system).

The drive mechanism 30 can move the head unit 20 in the verticaldirection and the horizontal direction with respect to the base unit 80.In addition, the head unit 20 can be inclined in an arbitrary directionwith respect to the vertical direction or the horizontal direction.

The drive mechanism 30 includes two arms 31 a and 31 b, five rotationsupport mechanisms 32 a, 32 b, 32 c, 32 d, and 32 e, five driving units33 a, 33 b, 33 c, 33 d, and 33 e that respectively drive the rotationsupport mechanisms, and supports 35 a, 35 b, 35 c, and 35 d. Each of therotation support mechanisms 32 a, 32 b, 32 c, 32 d, and 32 e is providedfor the arm or the support, and allows the counterpart arm or supportconnected thereto to rotate about an axis 34 a, 34 b, 34 c, 34 d, or 34e. Specifically, each of the rotation support mechanisms is a mechanismthat rotatably holds a shaft body connecting two members (the arms, thesupports, or the arm and the support). The driving units 33 a, 33 b, 33c, 33 d, and 33 e are, for example, motors each of which generates adriving force for rotating an associated one of the rotation supportmechanisms 32 a, 32 b, 32 c, 32 d, and 32 e. Specifically, each drivingunit is, for example, a mechanism including a combination of a DC motorand an encoder, and can be controlled at a predetermined rotation angle.Each driving unit may be a stepping motor. Further, the motor may beintegrated with a speed reducer. In the present specification, thedriving unit and an associated one of the rotation support mechanismsare illustrated as an integrated part. For example, the rotation supportmechanism 32 a and the driving unit 33 a for driving the rotationsupport mechanism unit 32 a are indicated by the reference character “32a(33 a).” Note that the rotation support mechanism and the driving unitmay be configured as separate parts. For example, the rotation supportmechanism may be a mechanism that holds the shaft body using a bearing,and the driving unit may be configured to transmit a rotational drivingforce to a geared shaft body held by the bearing via a reduction gear.

The configuration of the drive mechanism 30 will be described in moredetail below. The arm 31 a is connected to the base unit 80 via thesupport 35 b and the support 35 a fixed to the base unit 80. Morespecifically, the support 35 b is connected to the support 35 a fixed tothe base unit 80 to be rotatable about the axis 34 a by the rotationsupport mechanism 32 a (corresponding to a first rotation supportmechanism) provided for the support 35 a. Further, the arm 31 a isconnected to the support 35 b to be rotatable about the axis 34 b by therotation support mechanism 32 b (corresponding to a second rotationsupport mechanism) provided for the support 35 b. The arm 31 b isconnected to the arm 31 a to be rotatable by the rotation supportmechanism 32 c (corresponding to the second rotation support mechanism)provided for the arm 31 a. The arm 31 b and the head unit 20 areconnected together via the supports 35 c and 35 d. More specifically,the support 35 c is connected to the arm 31 b to be rotatable about theaxis 34 d via the rotation support mechanism 32 d (corresponding to thesecond rotation support mechanism) provided for the arm 31 b. Thesupport 35 d is connected to the support 35 c to be rotatable about theaxis 34 e via the rotation support mechanism 32 e (corresponding to thefirst rotation support mechanism) provided for the support 35 c. Each ofthe rotation support mechanisms may be provided for a member to beconnected.

In FIGS. 1 and 2 , the axes 34 a and 34 e are axes that can be orientedin the Y direction, i.e., the vertical direction, and these two axes 34a and 34 e correspond to an example of a first axis of the presentdisclosure. The axes 34 b, 34 c, and 34 d are axes that can be orientedin the X direction, i.e., the horizontal direction, and these three axes34 b, 34 c, and 34 d correspond to an example of a second axis of thepresent disclosure. Note that the axes are not necessarily in theabove-described relationship in the process in which the drive mechanism30 is operated.

FIG. 3 is a block diagram illustrating electrical connection amongcomponents of the ophthalmologic apparatus 10 of the first embodiment. Acontrol unit 71 is a controller incorporated in the base unit 80. Thecontrol unit 71 can instruct the light source 21 to irradiate thesubject's eye E with light. The control unit 71 can also receiveinformation from the imaging camera 22, analyze the received capturedimage data, and display the captured image data and the analysis resulton the q 74. The alignment detection unit 72 can calculate informationabout the position of the subject's eye relative to the head unit basedon the information from the stereo camera 23. Based on the informationabout the relative position calculated by the alignment detection unit72, the control unit 71 can control some of the driving units 33 a, 33b, 33 c, 33 d, and 33 e as needed to move the head unit 20 so that thehead unit 20 and the subject's eye E have an appropriate positionalrelationship.

A gaze position detection unit 73 has the function of receiving thecaptured image data input from the imaging camera 22 via the controlunit 71, detecting a gaze position of the subject's eye E, calculating agaze direction from the detected gaze position, and transmitting thecalculated gaze direction to the control unit 71. The gaze positiondetection unit 73 can detect the gaze position of the subject's eye Eby, for example, a gaze direction detection method (corneal detectionmethod) using a Purkinje image. The near-infrared light enters thesubject's eye E from the light source 21. The near-infrared lightincident from the point light source generates a Purkinje image, whichis the reflection of the near-infrared light, on a surface of a corneaEa of the subject's eye E. The position of the Purkinje image changes inaccordance with the change in the gaze direction of the subject's eye E.Thus, the gaze position detection unit 73 can detect positioncoordinates C1 of the Purkinje image on the subject's eye E based on thecaptured image data of the subject's eye E entered from the imagingcamera 22. Then, the gaze position detection unit 73 can detect the gazedirection of the subject's eye E based on the position (gaze position)of the center of a pupil relative to the position of the Purkinje imageindicated by the position coordinates C1. Note that the gaze directionmay be detected by any other method.

The gaze position detecting unit 73 detects the position of thesubject's eye E relative to the imaging camera 22 based on the capturedimage data. Note that the method for detecting the relative position ofthe subject's eye E is not particularly limited. In this case, the gazeposition detection unit 73 functions as a subject's eye positiondetection unit that detects the position of the subject's eye E relativeto the head unit 20.

Next, how the ophthalmologic apparatus 10, in particular, the drivemechanism 30, is operated will be described. The control unit 71controls the driving unit 33 a to allow the support 35 b and the arm 31a connected thereto to rotate about the axis 34 a, and allow the headunit 20 to change its orientation (inclination) in an XZ plane. Thecontrol unit 71 controls the driving unit 33 b to allow the arm 31 a torotate about the axis 34 b, and allow the head unit 20 to change itsposition in the X, Y, and Z directions, or its inclination(orientation). The control unit 71 controls the driving unit 33 c toallow the arm 3 lb to rotate about the axis 34 c, and allow the headunit 20 to change its position in the X, Y, and Z directions, or itsinclination (orientation). The control unit 71 controls the driving unit33 d to allow the support 35 c to rotate about the axis 34 d, and allowthe head unit 20 to change its inclination (orientation). Further, thecontrol unit 71 controls the driving unit 33 e to allow the support 35 dto rotate about the axis 34 e, and allow the head unit 20 to change itsorientation (inclination).

Controlling the driving units 33 a, 33 b, 33 c, 33 d, and 33 e in thismanner, the control unit 71 allows the head unit 20 to move to anarbitrary position in an XYZ space, and to incline in an arbitrarydirection or change its orientation. Based on the gaze position of thesubject's eye E detected by the gaze position detection unit 73(detection result), the control unit 71 can control the driving units 33a, 33 b, 33 c, 33 d, and 33 e to orient the head unit 20 so that theoptical axis O1 of the examination optical system and the gaze directionsubstantially coincide with each other. Further, the control unit 71 maycontrol the driving units 33 a, 33 b, 33 c, 33 d, and 33 e to orient thehead unit 20 so that the optical axis O1 of the examination opticalsystem deviates from the gaze direction with respect to the gazedirection. For example, when obtaining a cross-sectional image of an eyeE of a subject having a cataract through capturing a fundus image orOCT, the head unit 20 is oriented so that the optical axis O1 of theexamination optical system avoids a cloudy portion of the lens of thesubject's eye E. This makes it possible to examine the eye of thesubject having a cataract. In this way, the head unit 20 can bearbitrarily positioned or oriented with respect to the subject's eye E,which makes it possible to examine the subject's eye E at an arbitraryposition, or in an arbitrary direction.

Further, if the driving units are controlled in synchronization, theposition of the head unit 20 can be changed while maintaining theinclination and orientation of the head unit 20. This can move the headunit 20 with its posture maintained, so that the optical axis O1 of theexamination optical system is aligned with a direction toward thesubject's eye E.

Further, if the driving units are controlled in synchronization, theinclination and orientation of the head unit 20 can be changed whileallowing the optical axis O1 of the examination optical system to passan eye rotation center, which is the center of rotation of the subject'seye E, or its vicinity (substantial eye rotation center).

The alignment detection unit 72 can calculate the information about theposition of the subject's eye E relative to the head unit 20 based onthe information from the stereo camera 23. For example, determining thatthe position of the subject's eye E relative to the head unit 20 is farfrom an appropriate position, i.e., they have a great distance in the Xdirection, the control unit 71 drives the driving units 33 d, 33 c, and33 b in synchronization to cause the head unit 20 to move to the right,which is the Z direction in FIG. 1 , while maintaining the posture, andthe position in the Y direction, of the head unit 20. The control unit71 may control the drive mechanism 30 in accordance with the distanceinformation from the alignment detection unit 72 to move the head unit20, or may perform feedback control using the information about therelative position sequentially output from the alignment detection unit72 to move the head unit 20.

Further, the control unit 71 may control the respective driving units inaccordance with an operation through the operating unit 75 to move thehead unit 20.

As can be seen in the foregoing, according to the ophthalmologicapparatus 10 of the embodiment of the present disclosure, theophthalmologic apparatus 10 which is downsized, and gives the head unit20 an increased degree of positioning freedom can be provided withoutusing a slide mechanism. Further, the structure can be simplified whileimproving the degree of positioning freedom of the head unit 20.Controlling the drive mechanism 30 in accordance with the informationfrom the alignment detection unit 72, the control unit 71 can cause thehead unit 20 and the subject's eye E to be automatically aligned witheach other to be in an appropriate positional relationship.

Variation of First Embodiment

A variation of the ophthalmologic apparatus 10 according to the firstembodiment will be described below. In this variation, unlike the firstembodiment, one of the arms can rotate and move only in the horizontaldirection. FIG. 4 is a schematic view illustrating, in an enlargedscale, a drive mechanism 30′ of the ophthalmologic apparatus 10 as avariation of the drive mechanism of the ophthalmologic apparatusaccording to the first embodiment.

The drive mechanism 30′ includes two arms 31 a′ and 31 b′, five rotationsupport mechanisms 32 a′, 32 b′, 32 c′, 32 d′, and 32 e′, five drivingunits 33 a′, 33 b′, 33 c′, 33 d′, and 33 e′ that respectively drive therotation support mechanisms, and supports 35 a′, 35 b′, 35 c′, and 35d′. Each of the rotation support mechanisms 32 a′, 32 b′, 32 c′, 32 d′,and 32 e′ is provided for the arm or the support, and allows thecounterpart arm or support connected thereto to rotate about an axis 34a′, 34 b′, 34 c′, 34 d′, or 34 e′.

The configuration of the drive mechanism 30′ will be described in moredetail below. The arm 31 a′ is connected to the base unit 80 to berotatable about the axis 34 a′ by the support 35 a′ fixed to the baseunit 80 and the rotation support mechanism 32 a′ (corresponding to asecond rotation support mechanism) provided for the support 35 a′. Thisallows the arm 31 a′ to rotate and move in the horizontal direction. Thearm 31 b′ is connected to the arm 31 a′ via the support 35 b′. Morespecifically, the support 35 b′ is connected to the arm 31 a′ to berotatable about the axis 34 b′ via the rotation support mechanism 32 b′(corresponding to the second rotation support mechanism) provided forthe arm 31 a′. The arm 31 b′ is connected to the support 35 b′ to berotatable about the axis 34 c′ via the rotation support mechanismportion 32 c′ (corresponding to a first rotation support mechanism)provided for the support 35 b′. The arm 31 b′ and the head unit 20 areconnected together via the supports 35 c′ and 35 d′. More specifically,the support 35 c′ is connected to the arm 31 b′ to be rotatable aboutthe axis 34 d′ via the rotation support mechanism 32 d′ (correspondingto the first rotation support mechanism) provided for the arm 31 b′. Thesupport 35 d′ is connected to the support 35 c′ to be rotatable aboutthe axis 34 e′ via the rotation support mechanism 32 e′ (correspondingto the second rotation support mechanism) provided for the support 35c′. Each of the rotation support mechanisms may be provided for a memberto be connected.

In FIG. 4 , the axes 34 c′ and 34 d′ are axes that can be oriented inthe X direction, i.e., the horizontal direction, and the two axes 34 c′and 34 d′ correspond to an example of a first axis of the presentdisclosure. The axes 34 a′, 34 b′, and 34 e′ are axes that can beoriented in the Y direction, i.e., the vertical direction, and the threeaxes 34 a′, 34 b′, and 34 e′ correspond to an example of a second axisof the present disclosure. Note that the axes are not necessarily in theabove-described relationship in the process in which the drive mechanism30′ is operated.

Next, how the drive mechanism 30′ is operated will be described below.The control unit 71 controls the driving unit 33 a′ to allow the arm 31a′ to rotate about the axis 34 a′, and allow the head unit 20 to changeits position in the X, Y, and Z directions, or its orientation(inclination). The control unit 71 controls the driving unit 33 b′ toallow the support 35 b′ to rotate about the axis 34 b′, and allow thehead unit 20 to change its position in the X, Y, and Z directions, orits orientation (inclination). The control unit 71 controls the drivingunit 33 c′ to allow the arm 31 b′ to rotate about the axis 34 c′, andallow the head unit 20 to change its position in the X, Y, and Zdirections, or its inclination (orientation). The control unit 71controls the driving unit 33 d′ to allow the support 35 c′ to rotateabout the axis 34 d′, and allow the head unit 20 to change itsinclination (orientation). The control unit 71 controls the driving unit33 e′ to allow the support 35 d′ to rotate about the axis 34 e′, andallow the head unit 20 to change its orientation (inclination).Controlling the driving units 33 a′, 33 b′, 33 c′, 33 d′, and 33 e′ inthis manner, the control unit 71 allows the head unit 20 to move to anarbitrary position in an XYZ space, and to incline in an arbitrarydirection or change its orientation.

As can be seen in the foregoing, even if the drive mechanism isconfigured such that one of the arms is capable of rotating and movingonly in the horizontal direction, and two of the five axes are orientedin the horizontal direction and the remaining three axes are oriented inthe vertical direction, the head unit 20 is allowed to move to anarbitrary position in the XYZ space, and to incline in an arbitrarydirection or change its orientation, in the same manner as in the firstembodiment.

Another Variation of First Embodiment

Another variation of the ophthalmologic apparatus 10 according to thefirst embodiment will be described below. In this variation, unlike thefirst embodiment, an additional rotation support mechanism is providedbetween the two arms. FIG. 5 is a schematic perspective viewillustrating another variation of the drive mechanism of theophthalmologic apparatus according to the first embodiment.

A drive mechanism 30″ includes two arms 31 a″ and 31 b″, six rotationsupport mechanisms 32 a″, 32 b″, 32 c″, 32 d″, 32 e″, and 32 f″, sixdriving units 33 a″, 33 b″, 33 c″, 33 d″, 33 e″, and 33 f″ thatrespectively drive the rotation support mechanisms, and supports 35 a″,35 b″, 35 c″, 35 d″, and 35 e″. Each of the rotation support mechanisms32 a″, 32 b″, 32 c″, 32 d″, 32 e″, and 32 f″ is provided for the arm orthe support, and allows the counterpart arm or support connected theretoto rotate about an axis 34 a″, 34 b″, 34 c″, 34 d″, 34 e″, or 34 f″.

The configuration of the drive mechanism 30″ will be described in moredetail below. The arm 31 a″ is connected to the base unit 80 via thesupport 35 b″ and the support 35 a″ fixed to the base unit 80. Morespecifically, the support 35 b″ is connected to the support 35 a″ fixedto the base unit 80 to be rotatable about the axis 34 a″ by the rotationsupport mechanism 32 a″ (corresponding to a first rotation supportmechanism) provided for the support 35 a″. Further, the arm 31 a″ isconnected to the support 35 b″ to be rotatable about the axis 34 b″ bythe rotation support mechanism 32 b″ (corresponding to a second rotationsupport mechanism) provided for the support 35 b″. The arm 31 b″ isconnected to the arm 31 a″ via the support 35 c″. More specifically, thesupport 35 c″ is connected to the arm 31 a″ to be rotatable about theaxis 34 c″ via the rotation support mechanism 32 c″ (corresponding tothe first rotation support mechanism) provided for the arm 31 a″. Thearm 31 b″ is connected to the support 35 c″ to be rotatable about theaxis 34 d″ via the rotation support mechanism portion 32 d″(corresponding to the second rotation support mechanism) provided forthe support 35 c″. The arm 31 b″ and the head unit 20 are connectedtogether via the supports 35 d″ and 35 e″. More specifically, thesupport 35 d″ is connected to the arm 31 b″ to be rotatable about theaxis 34 e″ via the rotation support mechanism 32 e″ (corresponding tothe first rotation support mechanism) provided for the arm 31 b″. Thesupport 35 e″ is connected to the support 35 d″ to be rotatable aboutthe axis 34 f″ via the rotation support mechanism 32 r (corresponding tothe second rotation support mechanism) provided for the support 35 d″.Each of the rotation support mechanisms may be provided for a member tobe connected.

In FIG. 5 , the axes 34 a″, 34 c″, and 34 e″ are axes that can beoriented in the Y direction, i.e., the vertical direction, and the threeaxes 34 a″, 34 c″ and 34 e″ correspond to an example of a first axis ofthe present disclosure. The axes 34 b″, 34 d″, and 34 f″ are axes thatcan be oriented in the X direction, i.e., the horizontal direction, andthe three axes 34 b″, 34 d″, and 34 f″ correspond to an example of asecond axis of the present disclosure. Note that the axes are notnecessarily in the above-described relationship in the process in whichthe drive mechanism 30″ is operated.

Next, how the drive mechanism 30″ is operated will be described below.The control unit 71 controls the driving unit 33 a″ to allow the support35 b″ and the arm 31 a″ connected thereto to rotate about the axis 34a″, and allow the head unit 20 to change its orientation (inclination)in an XZ plane. The control unit 71 controls the driving unit 33 b″ toallow the arm 31 a″ to rotate about the axis 34 b″, and allow the headunit 20 to change its position in the X, Y, and Z directions, or itsinclination (orientation). The control unit 71 controls the driving unit33 c″ to allow the support 35 c″ to rotate about the axis 34 c″, andallow the head unit 20 to change its position in the X, Y, and Zdirections, or its inclination (orientation). The control unit 71controls the driving unit 33 d″ to allow the arm 31 b″ to rotate aboutthe axis 34 d″, and allow the head unit 20 to change its position in theX, Y, and Z directions, or its inclination (orientation). The controlunit 71 controls the driving unit 33 e″ to allow the support 35 d″ torotate about the axis 34 e″, and allow the head unit 20 to change itsinclination (orientation). The control unit 71 controls the driving unit33 f″ to allow the support 35 e″ to rotate about the axis 34 f″, andallow the head unit 20 to change its orientation (inclination).

As can be seen in the foregoing, using the drive mechanism including thethree axes oriented in the horizontal direction and the remaining threeaxes oriented in the vertical direction, the control unit 71 controlsthe driving units 33 a″, 33 b″, 33 c″, 33 d″, 33 e″, and 33 f″ to allowthe head unit 20 to move to an arbitrary position in the XYZ space, andto incline in an arbitrary direction or change its orientation. Havingsix rotation axes, the drive mechanism 30″ can move the head unit 20more smoothly than the drive mechanism having five rotation axes.

The drive mechanism 30 of the present embodiment is not limited to havetwo arms, and may have three or more arms. Further, the number of therotation support mechanisms may be five or more, and the number of thedriving units may be five or more.

Second Embodiment

A second embodiment of the present disclosure will be described below.An ophthalmologic apparatus 10A according to the second embodiment is anapparatus that can acquire information simultaneously from both eyes ofthe subject, and has two head units respectively provided for thesubject's right and left eyes to conduct simultaneous examination of theeyes.

FIG. 6 is a perspective view illustrating head units and drivemechanisms of the ophthalmologic apparatus 10A of the second embodiment.FIG. 6 shows head units 20L and 20R, drive mechanisms 30L and 30R, and aframe unit 85 of the ophthalmologic apparatus 10A, but other componentsare not shown. Although not shown, the chin support and the foreheadsupport described in the first embodiment may be provided for theophthalmologic apparatus 10A to fix the face of the subject. FIG. 7 is ablock diagram illustrating connection among components of theophthalmologic apparatus 10A of the second embodiment. The configurationof the ophthalmologic apparatus 10A of the second embodiment will bedescribed below with reference to FIGS. 6 and 7 . The same referencecharacters are given to the same components as those of the firstembodiment, and a description thereof is omitted. The subject's left eyewill be denoted by reference character EL, and a cornea of the subject'seye EL by reference character EaL. Likewise, the subject's right eyewill be denoted by reference character ER, and a cornea of the subject'seye ER by reference character EaR.

In FIG. 6 , the left drive mechanism 30L and the right drive mechanism30R are connected to the frame unit 85 fixed to a support column (notshown) supported by a base unit of the ophthalmologic apparatus 10A. Theleft head unit 20L is connected to the left drive mechanism 30L, and theright head unit 20R is connected to the right drive mechanism 30R.Specifically, the left head unit is paired with the left drivemechanism, and the right head unit is paired with the right drivemechanism. The two head units 20L and 20R are configured to be able toreceive light reflected from the subject's right and left eyes EL andER, respectively.

A drive mechanism 30L includes two arms 31 aL and 31 bL, six rotationsupport mechanisms 32 aL, 32 bL, 32 cL, 32 dL, 32 eL, and 32 fL, sixdriving units 33 aL, 33 bL, 33 cL, 33 dL, 33 eL, and 33 fL thatrespectively drive the rotation support mechanisms, and supports 35 aL,35 bL, 35 cL, and 35 dL. Each of the rotation support mechanisms 32 aL,32 bL, 32 cL, 32 dL, 32 eL, and 32 fL is provided for the arm or thesupport, and allows the counterpart arm or support connected thereto torotate about an axis 34 aL, 34 bL, 34 cL, 34 dL, 34 eL, or 34 fL.

The configuration of the drive mechanism 30L will be described in moredetail below. The arm 31 aL is connected to the frame unit 85 via thesupport 35 aL. More specifically, the support 35 aL is connected to berotatable about the axis 34 aL by the rotation support mechanism 32 aL(corresponding to a first rotation support mechanism) provided for thesupport 35 aL. Further, the arm 31 aL is connected to the support 35 aLto be rotatable about the axis 34 bL by the rotation support mechanism32 bL (corresponding to a second rotation support mechanism) providedfor the arm 31 aL. The arm 31 bL is connected to the arm 31 aL via thesupport 35 bL. More specifically, the support 35 bL is connected to thearm 31 aL to be rotatable about the axis 34 cL via the rotation supportmechanism 32 cL (corresponding to the second rotation support mechanism)provided for the support 35 bL. The arm 31 bL is connected to thesupport 35 bL to be rotatable about the axis 34 dL via the rotationsupport mechanism 32 dL (corresponding to the first rotation supportmechanism) provided for the arm 31 bL. The arm 31 bL and the head unit20L are connected together via the supports 35 cL and 35 dL. Morespecifically, the support 35 cL is connected to the arm 31 bL to berotatable about the axis 34 eL via the rotation support mechanism 32 eL(corresponding to the second rotation support mechanism) provided forthe support 35 cL. The support 35 dL is connected to the support 35 cLto be rotatable about the axis 34 fL via the rotation support mechanism32 fL (corresponding to the first rotation support mechanism) providedfor the support 35 dL. The head unit 20L is connected to the support 35dL. Each of the rotation support mechanisms may be provided for a memberto be connected.

In FIG. 6 , the axes 34 aL, 34 dL, and 34 fL are axes that can beoriented in the Y direction, i.e., the vertical direction, and the threeaxes 34 aL, 34 dL and 34 fL correspond to an example of a first axis ofthe present disclosure. The axes 34 bL, 34 cL, and 34 eL are axes thatcan be oriented in the X direction, i.e., the horizontal direction, andthe three axes 34 bL, 34 cL and 34 eL correspond to an example of asecond axis of the present disclosure. Note that the axes are notnecessarily in the above-described relationship in the process in whichthe drive mechanism 30L is operated.

The drive mechanism 30R and the drive mechanism 30L are symmetrical inshape. Components of the drive mechanism 30R have the same functions andreference characters as those of the drive mechanism 30L except that “R”in the reference characters replaces “L.”

The left and right head units 20L and 20R are provided as a pair toindividually correspond to the subject's left and right eyes. The lefthead unit 20L acquires information of the subject's left eye EL, and theright head unit 20R acquires information of the subject's right eye ER.

A mirror 24L, which is a deflection member, is provided for the lefthead unit 20L. The information of the corresponding subject's eye EL isacquired by the examination optical system through the mirror 24L. Theleft head unit 20L is provided with an examination optical system foracquiring ocular information of the subject's eye EL. The examinationoptical system includes an illumination optical system including a lightsource 21L that irradiates the anterior segment and fundus of thesubject's eye EL with illumination light, an imaging optical systemincluding an imaging camera 22L for acquiring images of the anteriorsegment and fundus of the subject's eye EL. The head unit 20L alsoincludes a stereo camera 23L for alignment adjustment so that anappropriate distance is kept between the subject's eye EL and the headunit 20L.

Components of the right head unit 20R have the same functions andreference characters as those of the left head unit 20L except that thealphabet “R” in the reference characters replaces the alphabet “L.”

FIG. 7 shows a block diagram modified from the block diagram of thefirst embodiment shown in FIG. 3 to correspond to the left and righthead units 20L and 20R and the left and right drive mechanisms 30L and30R.

Next, how the drive mechanism 30L is operated will be described below.The control unit 71 controls the driving unit 33 aL to allow the support35 aL and the arm 31 aL connected thereto to rotate about the axis 34aL, and allow the head unit 20L to change its orientation (inclination)in an XZ plane. The control unit 71 controls the driving unit 33 bL toallow the arm 31 aL to rotate about the axis 34 bL, and allow the headunit 20L to change its position in the X, Y, and Z directions, or itsinclination (orientation). The control unit 71 controls the driving unit33 cL to allow the support 35 bL to rotate about the axis 34 cL, andallow the head unit 20L to change its position in the X, Y, and Zdirections, or its inclination (orientation). The control unit 71controls the driving unit 33 dL to allow the arm 31 bL to rotate aboutthe axis 34 dL, and allow the head unit 20L to change its position inthe X, Y, and Z directions, or its inclination (orientation). Thecontrol unit 71 controls the driving unit 33 eL to allow the support 35cL to rotate about the axis 34 eL, and allow the head unit 20L to changeits inclination (orientation). The control unit 71 controls the drivingunit 33 fL to allow the support 35 dL to rotate about the axis 34 fL,and allow the head unit 20L to change its orientation (inclination). Thedrive mechanism 30R is operated in the same manner as the drivemechanism 30L except that the alphabet “R” in the reference charactersreplaces the alphabet “L.”

Controlling the drive mechanisms 30L and 30R, i.e., the driving units 33aL, 33 bL, 33 cL, 33 dL, 33 eL, 33 fL, 33 aR, 33 bR, 33 cR, 33 dR, 33eR, and 33 fR, in this manner, the control unit 71 allows each of thehead units 20L and 20R to move to an arbitrary position in an XYZ space,and to incline in an arbitrary direction or change its orientation.Thus, the head units 20L and 20R can be arbitrarily positioned ororiented with respect to the subject's eyes EL and ER, which makes itpossible to examine the subject's eyes EL and ER at an arbitraryposition, or in an arbitrary direction. Further, the control unit 71 cancontrol the drive mechanisms 30L and 30R using the detection result ofthe alignment detection unit 72, so that the head units 20L and 20R arealigned with and the subject's eyes EL and ER, respectively.

The gaze position detection unit 73 has the function of receiving thecaptured image data of the subject's left and right eyes EL and ERentered from the imaging cameras 22L and 22R via the control unit 71,detecting the gaze positions of the subject's eyes EL and ER,calculating the gaze directions from the detected gaze positions, andtransmitting the calculated gaze directions to the control unit 71.

Next, referring to FIGS. 8A and 8B, it will be described how each of thehead units 20L and 20R rotates in the direction of an XZ plane about theeye rotation center, which is the center of rotation, of an associatedone of the subject's eyes EL and ER. FIGS. 8A and 8B are schematic viewsof the ophthalmologic apparatus 10A as viewed from the top.

FIG. 8A shows the subject's eyes EL and ER facing the front (the -Zdirection). FIG. 8B shows the subject's eyes EL and ER in a near visionstate. In order to bring the subject's eyes EL and ER into the nearvision state, a fixation target (not shown) is used to guide the gaze ofthe subject's eyes EL and ER. Each of the subject's eye changes the gazedirection about the eye rotation center.

When the ophthalmologic apparatus 10A is used to perform, for example, aquantitative examination of squint in the near vision state, the controlunit 71 controls the drive mechanisms 30L and 30R to allow the headunits 20L and 20R to respectively rotate about the eye rotation centersof the subject's eyes EL and ER or the substantial eye rotation centersnear the eye rotation centers, and the subject is instructed to fixateon the fixation target displayed at a fixation target point PO that islocated forward by an examination distance from the subject's eyes E.This can bring the subject's eyes EL and ER into convergence, so thatthe eyes can gaze at the fixation target. If at least one of thesubject's eyes EL and ER has a heterophoria and cannot be fixated on thetarget, the control unit 71 controls the drive mechanisms 30L and 30R toallow the head units to rotate so that an angle of convergence θ isaligned with the subject's eyes.

Next, referring to FIGS. 9A and 9B, it will be described below how thehead unit 20L rotates in the direction of an YZ plane about the eyerotation center of the subject's eye EL. The following description isdirected to the left head unit 20L and the subject's eye EL, but thesame applies to the right head unit 20R and the subject's eye ER. FIGS.9A and 9B are schematic side views illustrating the left part of theophthalmologic apparatus 10A. FIG. 9A shows the subject's eye EL facingthe front (the -Z direction). FIG. 9B shows the subject's eye ELoriented downward. In order to orient the subject's eye EL downward, afixation target (not shown) is used to guide the gaze of the subject'seye EL. The subject's eye changes the gaze direction about the eyerotation center.

In the ophthalmologic apparatus 10A, in order to orient the gaze of thesubject's eye up or down, for example, the fixation target is displayedabove or below the subject's eye EL to guide the gaze. The control unit71 controls the drive mechanism 30L to allow the head unit 20L to rotateabout the eye rotation center of the subject's eye EL or the substantialeye rotation center near the eye rotation center.

Since the left and right head units 20L and 20R are respectivelyconnected to the independent drive mechanisms 30L and 30R, the subject'sleft and right eyes EL and ER can be examined in directions independentfrom each other.

As can be seen in the foregoing, being able to freely rotate in thedirections of the XZ plane and the YX plane, the left and right headunits 20L and 20R can be aligned with the subject's eyes in every gazedirection, such as far, near, up, down, left and right. Further, theoptical axis of the examination optical system can be independently setwith respect to the subject's left and right eyes EL and ER. Thus, forexample, when the subject has a heterophoria, even if the gaze direction(visual axis) of one of the subject's eyes (e.g., the subject's eye EL)meets the fixation target, the gaze direction of the other subject's eye(e.g., the subject's eye ER) deviates from the fixation target. In thiscase, the control unit 71 can control the orientation of the head unit20 (e.g., the head unit 20R) based on the gaze direction of the othersubject's eye (e.g., the subject's eye ER). Further, the gaze directionscan be detected using the results of detection of the gaze positions ofthe subject's eyes EL and ER by the gaze position detection unit 73. Inthis way, the present disclosure can address the examination and imaging(e.g., a heterophoria test in subjective tests, and peripheral imagingin fundus photography) performed in a state where the gaze direction(visual axis) of the subject's eye is in alignment with the optical axisof the examination optical system, and a state where the gaze direction(visual axis) is not in alignment. Further, as a use example in thestate where the gaze direction (visual axis) is not in alignment, anintended position can be targeted to conduct the examination whileavoiding a cloudy portion of the lens of each of the left and right eyesE of the subject having a cataract.

It has been described above that each of the drive mechanisms 30L and30R has two arms, but the number of the arms is not limited to two, andmay be three or more. The six rotation support mechanisms are notnecessarily required. Five or more rotation support mechanisms aresufficient, and five or more driving units will do.

Third Embodiment

A third embodiment of the present disclosure will be described below. Anophthalmologic system 1 of the third embodiment is a system thatconnects the ophthalmologic apparatuses 10 and 10A of the first andsecond embodiments to a network so that eye examination can be performedfrom a remote location, for example.

FIG. 10 is a block diagram illustrating the ophthalmologic system 1 ofthe third embodiment. The ophthalmologic system 1 of the presentembodiment is comprised of a terminal device 90 handled by a user and anophthalmologic apparatus 10 (10A) which are connected together via anetwork NW such as the Internet or a virtual private network (VPN).Examples of the terminal device 90 may include a personal computer (PC),a smartphone, a tablet PC, and a mobile terminal such as a mobile phone.

The ophthalmologic system 1 of the present embodiment makes it possibleto transmit examination information of the ophthalmologic apparatus 10(10A) to the terminal device 90 via the network NW. Further, the controlunit 71 may be instructed from the terminal device 90 via the network NWto control the drive mechanism 30 or any other components. As a result,for example, when a physician is physically at a distance (e.g., in aremote place) from the subject, the system can assist the physician inmaking a diagnosis of the subject's eye. In addition, the physician in aremote place can handle the terminal device 90 to control the drivemechanism 30 or any other components to adjust the positionalrelationship between the subject's eye and the head unit.

While some embodiments of the present disclosure have been describedabove, these embodiments may be implemented in various other forms, andvarious omissions, substitutions, and changes may be made withoutdeparting from the spirit of the invention. The embodiments andvariations thereof are included in the scope and spirit of theinvention, and are included in the invention described in the claims andtheir equivalents.

Note that in the above-described embodiments, the alignment is measuredusing a stereo camera, but this is not limiting. For example, as apossible method, the head unit may be provided with an alignment lightsource and a line sensor. The line sensor receives light emitted fromthe alignment light source and reflected from the subject's eye, and theposition of the subject's eye relative to the head unit is detectedbased on the information from the line sensor to adjust the alignment.

What is claimed is:
 1. An ophthalmologic apparatus for opticallyacquiring information of a subject's eye, the ophthalmologic apparatuscomprising: a head unit having an optical system capable of receivinglight reflected from the subject's eye; a drive mechanism that movablyholds the head unit; an alignment detection unit that detects a positionof the subject's eye relative to the head unit; and a control unit thatcontrols the drive mechanism, wherein the drive mechanism includes atleast two arms rotatably connected together, at least two first rotationsupport mechanisms each of which is rotatable about a first axis, atleast three second rotation support mechanisms each of which isrotatable about a second axis different in direction from the firstaxis, and at least five driving units for driving the first and secondrotation support mechanisms, the first and second rotation supportmechanisms allowing the head unit to move, and the control unit iscapable of controlling the driving units using a detection result of thealignment detection unit to align the head unit and the subject's eyewith each other.
 2. The ophthalmologic apparatus of claim 1, wherein theat least two arms are connected together via the first rotation supportmechanisms, and the at least two arms and the head unit are connected toeach other via the first rotation support mechanisms and the secondrotation support mechanisms.
 3. The ophthalmologic apparatus of claim 1,wherein the first axis is capable of being oriented in a verticaldirection, and the second axis is capable of being oriented in ahorizontal direction orthogonal to the first axis.
 4. The ophthalmologicapparatus of claim 1, wherein the first axis is capable of beingoriented in a horizontal direction, and the second axis is capable ofbeing oriented in a vertical direction orthogonal to the first axis. 5.The ophthalmologic apparatus of claim 1, wherein the control unit iscapable of controlling the driving units to allow the head unit to movewhile keeping an optical axis of the optical system passing an eyerotation center of the subject's eye or a substantial eye rotationcenter near the eye rotation center.
 6. The ophthalmologic apparatus ofclaim 1, wherein the control unit is capable of controlling the drivingunits to align an optical axis of the optical system with a directiontoward the subject's eye while maintaining a posture of the head unit.7. The ophthalmologic apparatus of claim 1, wherein the head unitincludes two alignment cameras, and the alignment detection unit detectsthe position of the subject's eye relative to the head unit based oninformation of images captured by the two alignment cameras.
 8. Theophthalmologic apparatus of claim 1, wherein the head unit includes analignment light source and a line sensor, and the line sensor receiveslight emitted from the alignment light source and reflected from thesubject's eye, and the alignment detection unit detects the position ofthe subject's eye relative to the head unit based on information fromthe line sensor.
 9. The ophthalmologic apparatus of claim 1, wherein theoptical system includes a fundus camera capable of capturing a fundusimage of the subject's eye by the light reflected from the subject'seye.
 10. The ophthalmologic apparatus of claim 1, wherein the opticalsystem includes an anterior segment camera capable of capturing an imageof an anterior segment of the subject's eye by the light reflected fromthe subject's eye.
 11. The ophthalmologic apparatus of claim 1, furthercomprising a gaze position detection unit that detects a gaze positionof the subject's eye, wherein the control unit is capable of controllingthe driving units to align the head unit with the subject's eye usingthe gaze position detected by the gaze position detection unit.